OK, so I got the car back together and went to drive it. There is a ticking noise coming from the rear somewhere, whether in gear or not. I put the car on jackstands, turned it on and put it in gear, to see if I could locate the sounds. Couldn't hear anything, but my left wheel wasn't really turning. Every second or two it woud rotate a tiny bit, and if I turned it with my hand, it felt like it wanted to go. Plus, the ticking noise is much louder when turning right, and almost nonexistant when turning left.
When I was removing the left rear strut, I forgot to unbolt the axle from the hub at first. Is it possible that I pulled the axle partially out of the differential when I did this?
Also, when up in the air and car turned off, in neutral, spinning one wheel does nothing to the other. In gear, they spin opposite directions, which I believe is normal.
Whatever the problem, I don't think I'll be able to fix it by next sundays track day.